Patent GB-132495-A (GB)
IPC: H04M1/272
Abstract: 132,495. Automatic Telephone Manufacturing Co., (Assignees of Homrighous, J. H.). Sept. 13, 1918, [Convention date]. Semi-automatic exchange systems.-An operator's impulse-sender comprises a single set of ten push buttons, adapted to be operated as many times as there are digits in the number to be transmitted, to determine the extent of movement of a step-by-step switching-mechanism which controls the transmission of impulses. A signal is automatically operated on completion of the final impulse of the last digit whatever the number of digits to be transmitted. The depression of the push buttons earths corresponding terminals of a rotary switch E, Fig. 6, which is operated in synchronism with the selectors D, &c., the arrangement being such that, when the thousands wiper reaches an earthed terminal, the switch is released and stops the transmission of impulses to the selector. This operation is repeated for the hundreds, tens, and units impulses. In order that the forty sets of springs 30 - - 69, Fig. 6, connected to the terminals of the switch E, may be operated by a single set of ten keys, a ratchet mechanism, operating on the depression of any key, shifts the levers &c. through which the keys operate the springs opposite a fresh set of ten springs, so that successive depression of the keys in accordance with the digits of the wanted number operates one set of springs in each group of ten. According to the Specification as open to inspection under Sect. 91 (3) (a), the rotary switch may be replaced by a set of counting-relays for controlling the transmission of impulses. This statement does not appear in the Specification as accepted. Keyboard mechanism. The sets of springs 30 - - 69, Fig. 6, are arranged in two rows on transverse bars 15, 16, Figs. 2 and 3, secured to the side plates 13, 14 of the machine. The keys 20 are also mounted in fixed relation to the side plates 13, 14 and operate the sets of springs through levers 17, 18 pivoted on shafts 82, 82<1> carried by a framework having horizontal members 75, 76, side members 74, 79, and parts 72, 73, 77, 78, Fig. 3, adapted to slide in holes in the side plates 13, 14 so that the framework and levers 17, 18 can be shifted transversely to bring the keys into operative relation with successive sets of springs. This transverse movement is effected by a ratchet member 95, Fig. 3, engaged by a pawl 96 connected to the armature of magnet 80, a detent 100 being controlled by the release magnet 70. On the depression of any key, according to the thousands digit of the wanted number, the lever 17 or 18 shifts the corresponding set of springs, which is retained by a catch 23 or 23<1>. The depression of the key also rocks shaft 82 (or 82<1>) to open contact 84 (or 87) and close contact 83 (or 86), thereby energizing relay 91, Fig. 5, which locks up over its upper winding and the armature of the magnet 80. On the restoration of the key, contact 83 is opened and contact 84 closed, thereby energizing the magnet 80, which shifts the levers 17, 18, &c. opposite the next set of springs. This operation is repeated on the depression of the hundreds and tens keys. When the operator depresses the release key at the end of the impulse transmission, magnet 70, Figs. 2 and 5, releases the catches 23, 23<1> and restores the framework carrying the levers 17, 18. Transmission of selecting-impulses. The sets of springs 30 - - 69 are connected to the terminals of switch E, the springs 30, 34, 38, &c. being connected to the contacts in the top level engaged by the thousands wiper 110, springs 31, 35, 39, &c. to the contacts in the second level engaged by the hundreds wiper 111, and so on. The springs 30 - - 69 also control four relays 150 - - 153, one relay being energized for each key depressed. The relays 162 - - 165 are energized successively after each train of impulses, and make the wipers 110 - - 113 operative in succession. In response to a call, the operator inserts the plug P of an idle selector trunk and depresses the key K to connect up her impulse-sender. The contact 137 of key K is closed before the other contacts, and energizes the relay 138 controlling the rotation of the switch E. The relay 138 energizes the stepping-relay 105 over a resistance 135, so that the impulse-relay 140 of the selector D is energized over leads 190, 194, low-resistance relay 131, and contact 114 of the relay 105. The operator then depresses her keys in accordance with the wanted number. The depression of the thousands key energizes relay 150, which opens contact 154 in the circuit of the controlling-relay 138, and as relay 131 has opened contact 139 in a parallel circuit, relay 138 de-energizes and opens the circuit over resistance 135 for the stepping-relay 105. Relay 105 is now repeatedly energized by the interrupted relay 134, and transmits impulses over contact 114 to the selector impulse relay 140 and to the actuating-magnet 108 of the rotary switch E. The selector and switch E operate in synchronism until the thousands wiper 110 of the switch reaches the terminal grounded by one of the sets of springs 30, 34, 38, &c., whereupon the controlling-relay 138 is again energized and maintains the circuit of the stepping-relay 105 over resistance 135. The release magnet 166 of the switch E is energized over the armatures of relay 138 and of a relay 196, energized on the first step of the switch. The switch E is thus released and the hundreds wiper 111 substituted for the thousands wiper 110 owing to the energization of relay 162 over a passing contact made by relay 138. Relay 162 locks up and also closes a further circuit for relay 138 over contact 176 and contact 155 of relay 151. The depression of the hundreds key energizes relay 151 to open this circuit, but the relay 138 is maintained energized until the slowrelease relay 131 (in circuit with the selector impulse relay) is de-energized, and this relay is adjusted so as to give time for the rotary hunting movement of the selector. When the controlling- relay 138 de-energizes, the operation of the switch E is repeated under control of the hundreds wiper 111, a second set of impulses being sent over the selector trunk. The process is repeated for the tens and units impulses. The relays 162 - - 165 and 150 - - 153 energize in succession. When the last series of impulses is completed, relay 165 energizes and closes a circuit for a relay 185, which lights the lamp L' to indicate to the operator that the impulse-transmission is complete. If the number to he called contains three digits only, the relay 185 is energized by relay 164. The operator then depresses the release key 200, which restores the keyboard mechanism to normal and opens the locking-circuits of the relays 162 - - 165, thereby restoring the switch E to normal condition.